1. Field of the Invention
This invention relates to circuit breakers which have mechanisms for adjusting the current at which the breaker trips and in particular to such circuit breakers which have a mechanism for assuring that the breaker is tripped before it is removed from its mountings.
2. Background Information
Circuit breakers provide a mechanism for opening the circuit through a single or multiphase electrical conductor within a protective enclosure, and typically are provided with means for suppressing the arcs created when large currents are interrupted. Some circuit breakers are provided with quick disconnect type terminals for engaging the electrical conductors in which they are inserted. If the circuit breaker is not tripped before it is disconnected from the conductor it is protecting, large unsuppressed arcs can be generated at the disconnects. This can be dangerous to those removing the breaker and can cause considerable damage to the circuit breaker and conductor terminals.
There is a need, therefore, for a circuit breaker which cannot be disconnected from the conductor it is protecting with the breaker contacts closed.
More specifically, there is a need for a circuit breaker which is automatically tripped as it is disconnected from the electrical conductor in which it is inserted.
There is a further need for such a circuit breaker which is tripped before it becomes disconnected from the electrical conductor.
Most circuit breakers have mechanisms for adjusting the abnormal current conditions under which the breaker trips. These mechanisms can make it more difficult to apply an interlock device for tripping the breaker as it is disconnected from the protected conductor. There is an additional need, therefore, for a circuit breaker with such a trip adjustment mechanism, which is tripped before the terminals become disconnected if an attempt is made to remove the circuit breaker with the circuit breaker contacts closed.
There is particular need for such a circuit breaker which is easily and inexpensively constructed or retrofitted to an existing breaker, yet is reliable.